Writing in the International Journal of Food Science and Technology, Korean researchers report that potassium chloride can partially replace sodium chloride in mackerel fish fillets, with ascorbic acid (vitamin C) added to ensure antioxidant preservation.
Salt is of course a vital nutrient and is necessary for the body to function, but campaigners for salt reduction, like the UK-based Consensus Action on Salt and Health (CASH) consider the average daily salt consumption in the western world, between 10 and 12g, far too high.
The UK has been leading the way in the and the Food Standards Agency’s (FSA) recommendation of six grams of salt per day for the general population is understood to be more a realistic target than the ideal healthy limit recommended by WHO/FAO.
The new research, led by Keum Hwang from Department of Food and Nutrition at Seoul National University, identifies alternatives for processed fish product producers to reduce the salt content of their products without detrimentally affecting key parameters such as flavour and shelf-life.
Hwang and his co-workers formulated fish fillets using different ratios of sodium chloride (NaCl) to potassium chloride (KCl), including 2:0, 1.5:0.5, 1:1, 0.5:1.5 and 0:2, always totally 2 per cent. Ascorbic acid was used at a concentration of 0.25 per cent.
According to results from sensory quality tests, the optimal reduction of sodium chloride, while simultaneously maintaining the sensory qualities, was observed for 50 per cent replacement with potassium chloride.
No significant differences were observed in terms of sourness when the salted mackerel fillets were formulated with or without vitamin C.
Oxidation processes in food can lead to organoleptic deterioration in taste, colour and texture. And fish products are particularly susceptible to oxidation processes because of the high unsaturated lipid content.
In terms of lipid oxidation and deterioration, vacuum packing and storing at 2 degrees Celsius produced the best results, wrote Hwang and his co-workers.
“The addition of ascorbic acid and the partial replacement of NaCl by KCl to mackerel fillets could retard lipid oxidation while decreasing the consumption of Na,” wrote the researchers.
“An adequate level of ascorbic acid would be 0.25 per cent, which could be used without influencing the taste of the fish. The most acceptable level of NaCl would be less than or equal to 2 per cent, half of which could be substituted with KCl without influencing the saltiness and bitterness of the fish.
“If the mackerel treated with ascorbic acid and NaCl and KCl is vacuum-packaged and stored frozen, it would maintain the best quality,” they concluded.
Earlier this year, scientists from Harvard Medical School reported in the Archives of Internal Medicine that higher sodium and lower potassium intakes may increase the risk of heart disease by 24 per cent.
The trials of hypertension prevention (TOHP) I and II – looked at the effects of sodium reduction and other interventions on the risk of cardiovascular disease (CVD). Researchers, led by Nancy Cook from Harvard Medical School, found that increasing levels of sodium in the urine increased the risk of CVD.
“The totality of evidence suggests that lowering dietary sodium intake, while increasing potassium consumption, at the population level might reduce the incidence of CVD,” wrote Cook.
Source: International Journal of Food Science and Technology
Published online ahead of print, doi: 10.1111/j.1365-2621.2008.01841.x
"Partial replacement of NaCl by KCl in salted mackerel (Scomber japonicus) fillet products: effect on sensory acceptance and lipid oxidation"
Authors: J.N. Park, K.T. Hwang, S.B. Kim, S.Z. Kim